Stoke Therapeutics Gets FDA Breakthrough Status for Dravet Syndrome Drug Zorevunersen

Stoke Therapeutics, Inc. (Nasdaq: STOK), a biotechnology firm specializing in RNA medicine to restore protein expression, has announced the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to its drug candidate zorevunersen. This drug is intended for patients with Dravet syndrome who have a confirmed mutation in the SCN1A gene that is not associated with gain-of-function. Zorevunersen is in development as a potential disease-modifying treatment for Dravet syndrome, making it a unique proposition in the field.

Clinical trials have demonstrated that zorevunersen significantly reduces seizure frequency and improves cognition and behavior over time. These benefits were observed even when patients were already on optimal anti-seizure medications. The drug has generally been well tolerated, with over 600 doses administered to patients, some of whom have been receiving treatment for more than three years.

Ongoing discussions with the FDA and international regulatory bodies are focused on the design of a global, randomized, controlled Phase 3 study for zorevunersen. Stoke Therapeutics plans to provide further updates on this Phase 3 study by the end of the year.

Chief Regulatory Affairs Officer, Shamim Ruff, expressed optimism about the FDA's Breakthrough Therapy designation. Ruff highlighted the promising clinical data supporting zorevunersen's potential to significantly improve treatment outcomes for Dravet syndrome compared to existing therapies. Ruff also emphasized the importance of working closely with the FDA to advance zorevunersen efficiently into the Phase 3 study.

Mary Anne Meskis, Executive Director of the Dravet Syndrome Foundation, also commented on the significance of this designation. She noted that many patients with Dravet syndrome continue to suffer from treatment-resistant seizures and other health issues despite the availability of symptomatic treatments. Meskis appreciated the FDA's recognition of the urgent need for innovative treatments that address the root cause of the disease.

The Breakthrough Therapy designation is intended to expedite the development and review of drugs that treat serious conditions and show potential for substantial improvement over existing therapies. This designation gives zorevunersen access to various benefits, including all features of Fast Track designation, detailed guidance on an efficient drug development program, and a high level of involvement from senior FDA managers.

Dravet syndrome is a severe, progressive genetic epilepsy characterized by frequent and prolonged seizures beginning in the first year of life. It is challenging to manage and often comes with a poor long-term prognosis. The disease's complications can severely impact the quality of life for both patients and their caregivers. These complications extend beyond seizures to include intellectual disability, developmental delays, balance and movement issues, language and speech disturbances, growth defects, sleep abnormalities, disruptions in the autonomic nervous system, and mood disorders. Classified as a developmental and epileptic encephalopathy due to the developmental delays and cognitive impairment it causes, Dravet syndrome also carries a higher risk of sudden unexpected death in epilepsy (SUDEP). No disease-modifying therapies are currently approved for Dravet syndrome, which affects approximately one in 16,000 babies globally.

Zorevunersen (STK-001) is an investigational medicine for Dravet syndrome that is undergoing clinical trials. It is a proprietary antisense oligonucleotide (ASO) designed to increase the expression of the NaV1.1 protein by targeting the non-mutant copy of the SCN1A gene. This approach aims to restore normal NaV1.1 levels, thereby reducing seizures and other comorbidities associated with Dravet syndrome. Zorevunersen has received orphan drug designation from both the FDA and the EMA, as well as rare pediatric disease designation from the FDA.

Stoke Therapeutics, headquartered in Bedford, Massachusetts, is a biotechnology company focused on developing RNA medicines to restore protein expression. Utilizing their proprietary TANGO (Targeted Augmentation of Nuclear Gene Output) approach, the company is developing antisense oligonucleotides to selectively restore protein levels. Their first compound, zorevunersen, is being tested for Dravet syndrome. Stoke is also developing STK-002 for autosomal dominant optic atrophy (ADOA), the most common inherited optic nerve disorder. The company’s research primarily targets haploinsufficiencies and diseases of the central nervous system and the eye, although their approach shows potential for broader applications.